Troubleshooting ZFS Dump Device Issues

Review the following items if you have problems either capturing a system
crash dump or resizing the dump device.

If a crash dump was not created automatically, you can use
the savecore command to save the crash dump.

A dump volume is created automatically when you initially
install a ZFS root file system or migrate to a ZFS root file system. In most
cases, you will only need to adjust the size of the dump volume if the default
dump volume size is too small. For example, on a large-memory system, the
dump volume size is increased to 40 GB as follows:

# zfs set volsize=40G rpool/dump

Resizing a large dump volume can be a time-consuming process.

If, for any reason, you need to enable a dump device after you create
a dump device manually, use syntax similar to the following:

A system with 128 GB or greater memory will need a larger
dump device than the dump device that is created by default. If the dump device
is too small to capture an existing crash dump, a message similar to the following
is displayed: